Bridging the Gap: Conference Record [Abstract book, International Conference on AIDS (12th: 1998: Geneva, Switzerland)]

1126 Abstracts 60681-60685

12th World AIDS Conference

Methods: Ultrasensitive quantitation of plasma HIV-RNA (Nasba Nuclisens,
Organon), 215 codon mutation in plasma HIV-RNA, human CCR5 genotype, and
serum anti-HIV antibody reactivity, were all investigated.
Results:
HIV-RNA (cop/ml) No. Months 215 mutation WB-pos A32CCR5 CD4+ fall
patients of treatment heterozyg (-15%)
-500 10 65 0 10 2 3
20-500 1 69 0 1 0 0
- 20 4 68 0 4 0 1
Total 15 67 0 15 2 4
Conclusions: The lack of emergence of ZDV-resistant viruses indirectly reflect
that effective control of HIV replication is taking place for an extended period of
time. Paradoxically, detectable viremia, although with very low titers, was recognized in most subjects. Meaning of this "residual viremia": i) ongoing virus
replication occurring in sanctuaries (CNS, etc) where ZDV does not achieve
appropriate levels; ii) HIV release from long-lived infected cells which could act
as cellular reservoirs where RT inhibitors, in fact, has a limited action; and iii)
circulating HIV-RNA genomes could be defective more often in subjects under
antiretroviral pressure.
60681 Circulating HIV-1 and HIV-2 genetic subtypes in Spain
Africa Molguin', B. Rodes2, V. Soriano2, J. Gonzalez-Lahoz2. 1Service
Infectious Diseases, ISC-III, Calle Sinesid Delgado 10, 28029 Madrid; 2lnstituto
Salud Carlos ///, Madrid, Spain
Objectives: To identify non-B HIV-1 and HIV-2 genetyc subtypes circulating in
Spain.
Design: We tested previously known 62 HIV-1 and 46 HIV-2 seropositive individuals living in Spain. Native born subjects as well as foreigners were included. A
genetic method based on RFLP targeting the protease gene from HIV-1 (Janini et
al. Virus Genes 1996; 3: 69-81) and the HIV-2 nefgene (Switzer etal. J Infect Dis,
in press) were used for this purpose. Proviral DNA extracted from PBMCs was
firstly amplified by nested-PCR, and sequential endonuclease restriction analysis
was performed on PCR products.
Results:

Subtypes
Immigrants
Spanish natives

HIV-1
A B C
13 16 2
2 22 1

HIV-2
A
30
11

Sequence analysis of the HIV-1 protease, p24 and/or V3 region was carried out
in some specimens, and confirmed the information provided by non-B subtypes
informed by RFLP. The 4 immigrants infected by HIV-2 subtype B came from
Equatorial Guinea and Ivory Coast. Some of the restriction patterns for HIV-2
subtype B samples were different from those previously reported, but were confirmed by DNA sequencing (nef and/or pol genes). Subjects with HIV-2 B variants
had low CD4 counts and AIDS (one died in 1995).
Conclusion: Different subtypes of HIV-1 and HIV-2 are currently circulating
in Spain, being non-B subtypes mostly confined to immigrants. Despite HIV-2
subtype A predominates over B, all HIV-2 subjects from Equatorial Guinea (a
former Spanish colony), carried HIV-2 B variants. AIDS caused by both HIV-2
subtypes were recognised, suggesting that both variants are pathogenic. These
results should be kept in mind for appropriate interpretation of serological and
viral load testing, which are based exclusively on HIV-1 subtype B
60682 1Prevalence of HIV and Chlamydia among adolescents
aged 15-19 years in rural Mwanza region, Tanzania:
A random sample survey
David Mabey1, David Ross12, J. Changalucha2, J. Todd12, F. Mosha2,
R. Balira2, R. Peeling3. 'London Sch. of Hygiene Tropical Medicine Keppel
Street London Wcie 7HT, England; 2NIMR, Mwanza, Tanzania; 3Laboratory
Centre for Disease Control, Winnipeg, Canada
Background: A community-randomized trial is being conducted in rural Tanzania
to assess the impact of an adolescent reproductive and sexual health intervention
on HIV incidence and other outcomes. In preparation for this, a survey of the
prevalence of HIV and Chlamydia trachomatis is being conducted in 400-420
adolescents aged 15-19 years in each of 23 rural wards in Mwanza Region.
Measured HIV and Chlamydia prevalences, together with other characteristics of
the wards, will be used to stratify them for subsequent randomization of 20 wards
to the intervention and comparison groups in the community-randomized trial.
Methods: A purposive sample of 23 wards was selected from four districts
in Mwanza Region, ensuring sufficient geographic separation to minimize contamination effects. Within each ward, 10 sub-villages were randomly selected,
and all those aged 14-20 years in these sub-villages were censused, and asked
to attend a convenient central location at which their age was checked and a
sample of urine collected. Subjects with blood in their urine were treated for schistosomiasis, and STD symptoms were treated syndromically. Further tests were
conducted only on samples from subjects aged 15-19 years. One aliquot of urine
was tested for HIV using a semi-quantitative particle agglutination test (GACPAT).
If positive or indeterminate, the urine was tested by ELISA (GACELISA), with
further confirmation by modified Western blot if necessary. A second aliquot of
urine was tested for Chlamydia trachomatis using PCR.

Results: Data and specimen collection will take place between November 1997
and May 1998, and laboratory analysis of urine will be completed by June. The
results of the survey will be presented at the conference.
Conclusions: Effective strategies to prevent HIV and other sexually transmitted diseases (STDs) in young people are recognized as an urgent priority, but
there are few reliable data on population prevalences of these infections among
adolescents in rural Africa. This survey will provide important data on age- and
sex-specific prevalences of HIV and chlamydia among adolescents aged 15-19
years in rural Tanzania, and will help to clarify the ages at which the incidence of
infection accelerates.
60683 Coreceptor usage by primary HIV-2 isolates
Andreas Mdrnerl, A. Bj6rndal1, J. Albert2, R. Thorstensson2, E.M. Feny61,
E. Bj6rling1. 1 MTC, Karolinska Institute, Box 280, 17177 Stockholm; 2Swedish
Inst. for Inf Disease Control, Stockholm, Sweden
Aims: To analyse the usage of the chemokine receptors CCR1, CCR2b, CCR3,
CCR5 and CXCR4 and the orphan receptors Bonzo and BOB by primary HIV-2
isolates. A possible correlation between CXCR4 utilisation and MT-2 tropism was
also investigated.
Material and Methods: U87 glioma cells stably expressing CD4 and one of
the chemokine receptors CCR1, CCR2b, CCR3, CCR5 or CXCR4 were used
for infection with twelve primary HIV-2 isolates. The experiments were carried
out both by cocultivation with infected PBMC and by cell-free infection. Cell-free
infection was also performed with CD4+ human osteosarcoma cells (HOS.CD4)
expressing the same chemokine receptors and Bonzo and BOB. MT-2 tropism
was tested both by cell-free infection and by cocultivation.
Results: All isolates, except 6669, were able to induce syncytia and HIV-2 ag
production in the CCR5 expressing U87.CD4 and HOS.CD4 cells. Two isolates,
1010 and 6669, were able to use CXCR4 for infection of both cell types. In
the U87.CD4 cells, several isolates were able to infect CCR1, CCR2b or CCR3
bearing cells. However, HOS.CD4 cells with these receptors were less permissable for infection. Several isolates also induced syncytia weakly in the parental
U87.CD4 cells. Five isolates could infect the HOS.CD4.BOB cells, whereas only
one infected the HOS.CD4.Bonzo cells. Three isolates, two of them CXCR4
users, induced typical syncytia in MT-2 cells.
Conclusions: CCR5 appeared to be the major coreceptor for the primary
HIV-2 isolates tested, whereas CXCR4 was only used by a few. A majority of
the isolates were also able to use at least one additional coreceptor. Unlike the
HIV-1 situation, there was no strict correlation between CXCR4 usage and MT-2
tropism.
60684 Multitropism of primary HIV-1 isolates
Asa Bj6rndall, C. Fracasso1, R. Fredriksont, D. Balfe2, H.R. Robinson3
E.M. Feny61. 'MTC, Karolinska Institute, Stockholm, Sweden; 2Dept. of
Virology, UCLMS, London, UK; 3Dept. of Virology, Univesity of Massachusetts,
Worcwster MA, USA
Aims: To study coreceptor usage of HIV-1 molecular clones, sequential primary
isolates and chimeric viruses constructed with their envelopes. We also investigated whether entry into monocyte-derived-macrophages (MDM) was restricted
to viruses with certain pattern of coreceptor usage.
Materials & Methods: For determining coreceptor usage, cell lines stably
expressing CD4 (U87.CD4) and chemokine-receptors CCR1, CCR2b, CCR3,
CCR5 and CXCR4 were used. For preparation of MDM, Ficoll-separated peripheral-mononuclear-cells (PBMC) were selected by adherence to plastic in the
presence or absence of human serum. At days 7 and 10 post-adherence cells,
were used for infection. Cultures were monitored by microscopy and p24 antigen,
both for extracellular production in the culture supernatant (U87 and MDM) and
intracellular expression (only MDM) using a monoclonal antibody to p24 and a
/f-gal conjugated secondary antibody.
Results: Studies of sequential virus isolates and chimeras constructed with
their envelopes showed a broadening of coreceptor usage over time. Broad coreceptor usage was not due to a mixture of viral variants with different phenotypes,
but was the property of a single envelope. All viruses productively infected MDM,
both multi-tropic viruses and mono-tropic for either CXCR4 or CCR5 (X4 and R5
viruses, respectively), including the T-cell-line adapted isolate IIIB. Increasing p24
antigen production was measured up to 17 days post infection, and at that time,
intracellular p24 antigen was demonstrated in infected cells.
Conclusions: The tropism of a primary isolate is not always reflected by clonal
envelopes. Moreover, isolates and cloned viruses had the capacity to infect and
establish a productive infection in MDM. This implies a functional role of both
CCR5 and/or CXCR4 in this cell type. Alternatively, the presence of another, so
far unidentified, coreceptor may mediate HIV-1 entry into macrophages.
| 60685 Inhibitory influences of a-MSH peptides on HIV-1
expression in monocytic cells

Wilma Barcellinil, A. Catania2, J.M. Lipton3, L. La Maestral, G. Clerici1.
'Internal Medicine, Ospedale Maggiore, Milano; 3Division of Hemathology,
Milano, Italy; 2Department of Physiology, UT Southwestern Medical Center,
Dallas TX, USA
Objectives: to investigate influences of the antiinflammatory peptides a-MSH
[1-13] and its COOH-terminal tripeptide Lys-Pro-Val, a-MSH [11-13], on HIV